Radio frequency identification device (RFID) systems are widely used for tracking and other applications in many different types of industries. A typical RFID system includes RFID tags and an RFID reader that reads information from the RFID tags. For example, the RFID reader includes a transmitter that outputs radio frequency (RF) signals through an antenna to create an electromagnetic field that the tags perturb to return their stored information to the reader. Some types of conventional tags are “passive” tags, such as tags without an internal power source that may be energized by the electromagnetic field generated by the reader, and “active tags”, such as tags with an internal power source.
Many RFID systems use tags to track goods. For example, a tag is attached to a palette of goods. The palette of goods is tracked using readers at various points in the supply chain. For example, a tag attached to a palette of goods in a warehouse is read to determine a unique identification for the palette of goods and possibly information about the goods. The information may be provided to inventory and tracking software for tracking the palette of goods through the supply chain.
It is known to provide tags on labels, and the labels may be attached to palettes of goods or large packaging, such as a box of goods. These labels may be large enough to accommodate an RFID antenna in the tag such that a reader may read the tag from a convenient distance. For RFID tags that use RF coupling, optimum antenna lengths are generally a function of the energizing signals wavelength.
Typically, tags are not provided on individual items. For example, components of a system, such as memory modules, processor chips, graphics cards, etc., may not be individually tagged, and thus may not be individually tracked before or after being delivered to a customer. One reason could be the relatively large size of the tag, which includes the antenna connected to an RFID chip. The size of the tag may not be able to be reduced because the antenna should be large enough to allow the tag to be read from a convenient distance. The tag may not fit on a label for an individual good or there may be no available surface for placing a tag on an individual good. Thus, it is difficult to track individual goods using an RFID system. Another possible reason tags are not provided on individual items is cost. A manufacturer or retailer may not be able to justify the cost of tag or the cost of adding a tag to individual goods, especially if profit margins are slim for a particular good.